21666344605166 has 8 divisors (see below), whose sum is σ = 32499536659824. Its totient is φ = 10833165718560.

The previous prime is 21666344605123. The next prime is 21666344605201. The reversal of 21666344605166 is 66150644366612.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a Curzon number.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 4776566 + ... + 8133158.

It is an arithmetic number, because the mean of its divisors is an integer number (4062442082478).

Almost surely, 2^{21666344605166} is an apocalyptic number.

21666344605166 is a deficient number, since it is larger than the sum of its proper divisors (10833192054658).

21666344605166 is a wasteful number, since it uses less digits than its factorization.

21666344605166 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 6584026.

The product of its (nonzero) digits is 22394880, while the sum is 56.

The spelling of 21666344605166 in words is "twenty-one trillion, six hundred sixty-six billion, three hundred forty-four million, six hundred five thousand, one hundred sixty-six".